Secure data management

ABSTRACT

The disclosed subject matter includes a method. The method includes identifying an attempt to access, by an application instance running in a user space of an operating system, a first security zone of a computer readable medium, where the first security zone is associated with a first security level. The method further includes determining whether a restriction level associated with the application instance is higher than the first security level, where the restriction level is a function of previous security zones that have been accessed by the application instance. When the restriction level associated with the application instance is higher than the first security level, the method would prevent the application instance from writing to the first security zone. When the restriction level associated with the application instance is not higher than the first security level, the method would authorize the application instance to access the first security zone.

CROSS-REFERENCE TO RELATED APPLICATION

This application is related to U.S. application Ser. No. TBD, entitled“SECURE DATA MANAGEMENT,” filed on the same date as the presentapplication, and bearing Attorney Docket No. 2207391-00171US1, which isincorporated by reference herein in its entirety.

BACKGROUND

Managing data security is an important task for computing systems.Oftentimes, a computer system maintains both public data andconfidential data. While public data can be accessed by a generalpublic, confidential data should only be accessed by selectedindividuals. Therefore, a computer system should control data accessbased on the authority granted to individuals.

A computer system can address this issue by associating a computerreadable medium with a security level and by associating an application(or a user operating the application) with an authority level. Forexample, if an application has an authority level that is less than thesecurity level associated with the computer readable medium, thecomputer system can prevent the application from accessing data in thecomputer readable medium.

Unfortunately, simply controlling data access is not sufficient toprevent data leakage, partially because a single application can accessmultiple data items simultaneously. For example, if an application witha high authority level retrieves a file from a computer readable mediumwith a high security level, and creates a new file, based on the “highsecurity” file, at another computer readable medium with a lowersecurity level, then another application with a lower authority levelcan access the new file and gain access to information that wasprotected at the high security level.

As another example, if an application with a high authority levelretrieves a file from a computer readable medium with a high securitylevel, and copies (i.e., cuts-and-pastes) information in the “highsecurity” file to a “low security” file stored in a low-securitycomputer readable medium, then another application with a lowerauthority level can access the “low security” file and gain access toinformation that was protected at the high security level.

Therefore, there is a need in the art to provide systems and methods forimproving the data security management. Accordingly, it is desirable toprovide methods and systems that overcome these and other deficienciesof the related art.

SUMMARY

In accordance with the disclosed subject matter, systems and methods areprovided for providing secure data management.

The disclosed subject matter includes a method. The method can includeidentifying, by a module in a computer system, an attempt to access, byan application instance running in a user space of an operating system,a first security zone of a computer readable medium, where the firstsecurity zone is associated with a first security level. The method canfurther include determining, by the module, whether a restriction levelassociated with the application instance is higher than the firstsecurity level, where the restriction level is a function of previoussecurity zones that have been accessed by the application instance. Whenthe restriction level associated with the application instance is higherthan the first security level, the method can include preventing theapplication instance from writing to the first security zone. When therestriction level associated with the application instance is not higherthan the first security level, the method can include authorizing theapplication instance to access the first security zone.

The disclosed subject matter also includes an apparatus. The apparatuscan include a non-transitory memory storing computer readableinstructions, and a processor in communication with the memory and witha non-transitory computer readable medium having a first security zone.The computer readable instructions are configured to cause the processorto receive a request, from an application instance running in a userspace of an operating system, to access the first security zone, wherethe first security zone is associated with a first security level, anddetermine whether a restriction level associated with the applicationinstance is higher than the first security level, where the restrictionlevel associated with the application instance is a function of previoussecurity zones that have been accessed by the application instance. Whenthe restriction level associated with the application instance is higherthan the first security level, the computer readable instructions areconfigured to cause the processor to prevent the application instancefrom accessing the first security zone. When the restriction levelassociated with the application instance is not higher than the firstsecurity level, the computer readable instructions are configured tocause the processor to authorize the application instance to access thefirst security zone.

The disclosed subject matter further includes a non-transitory computerreadable medium. The non-transitory computer readable medium can includeexecutable instructions operable to cause an apparatus to identify anattempt, by an application instance running in a user space of anoperating system, to access a first security zone of non-transitorymemory, wherein the first security zone is associated with a firstsecurity level. The executable instructions are also be operable tocause an apparatus to determine whether a restriction level associatedwith the application instance is higher than the first security level,where the restriction level associated with the application instance isa function of previous security zones that have been accessed by theapplication instance. The executable instructions can also be operableto cause an apparatus to prevent the application instance from writingto the first security zone when the restriction level associated withthe application instance is higher than the first security level. Theexecutable instructions can also be operable to cause an apparatus toauthorize the application instance to access the first security zonewhen the restriction level associated with the application instance isnot higher than the first security level.

In one aspect, the method, the apparatus, or the non-transitory computerreadable medium can include steps, modules, or executable instructionsfor determining whether the application instance is associated with anyrestriction level and for authorizing the application instance to accessthe first security zone when the application instance is not associatedwith any restriction level.

In one aspect, the method, the apparatus, or the non-transitory computerreadable medium can include steps, modules, or executable instructionsfor receiving a request, from the application instance, to authorize aread operation to a second security zone of the computer readablemedium, where the second security zone is associated with a secondsecurity level, for determining whether the restriction level associatedwith the application instance is higher than the second security level,and for modifying the restriction level of the application instance asthe second security level when the restriction level associated with theapplication instance is higher than the second security level.

In one aspect, the method, the apparatus, or the non-transitory computerreadable medium can include steps, modules, or executable instructionsfor determining whether the application instance is associated with anyrestriction level and for associating the application instance with arestriction level when the application instance is not associated withany restriction level, where the restriction level is set as the secondsecurity level.

In one aspect, the restriction level associated with the applicationinstance is a highest security level of all previous security zones thathave been accessed by the application instance.

In one aspect, wherein the steps, modules, or executable instructions ofthe method, the apparatus, or the non-transitory computer readablemedium are executed in a kernel space of the operating system.

In one aspect, wherein the steps, modules, or executable instructions ofthe method, the apparatus, or the non-transitory computer readablemedium are executed by a loadable kernel module in the kernel space ofthe operating system.

In one aspect, the association between the first security zone and thefirst security level is maintained in a configuration file stored in thenon-transitory memory.

In one aspect, the request to access the first security zone includes arequest to authorize a write operation to the first security zone.

It is to be understood that the disclosed subject matter is not limitedto the specific configurations described herein. Other embodiments arepossible. Also, the wording used herein is for the purpose ofdescription and should not be regarded as limiting.

BRIEF DESCRIPTION OF THE FIGURES

Various objects, features, and advantages of the disclosed subjectmatter can be more fully appreciated with reference to the followingdetailed description of the disclosed subject matter when considered inconnection with the following drawings, in which like reference numeralsidentify like elements.

FIG. 1 is a diagram of an exemplary networked communication system.

FIG. 2 is a diagram showing an exemplary process of how a module canpolice write privileges of an application instance.

FIGS. 3-5 are diagrams of exemplary processes for controlling writeprivileges of an application instance.

FIG. 6 is a diagram of an exemplary process for notifying a restrictionlevel of an application instance.

FIGS. 7A-7B are exemplary diagrams showing how a notificationapplication can modify an appearance of a status bar.

FIG. 8 is an illustration of an exemplary security level table.

FIG. 9 is a block diagram of an exemplary computing system.

DETAILED DESCRIPTION

Embodiments of the disclosed computer system can provide secure datamanagement. For example, a computer system can include a memory that isdivided into one or more computer security zones. The computer systemcan include a module that coordinates secure data management bymonitoring applications running on the computer system and detecting anyattempts by the application to access a particular security zone of thememory. When the module detects such an attempt, the module candetermine whether the application is authorized to do so. Based on thedetermination, the module can authorize and/or prevent the applicationfrom accessing the particular security zone.

To provide such a data management mechanism, the module can generallyinclude at least three functionalities. First, for example, the modulecan determine a restriction level of an application. The restrictionlevel can be indicative of the types of storage media or security zonesto which the application can write/read a data item. Second, forexample, the module can control write privileges of an application basedon the security level of storage media and the restriction level of theapplication. For example, if the restriction level of the application ishigher than the security level of a storage medium, the module canprevent the application from writing to the storage medium. Third, forexample, the module can cooperate with a notification application tonotify the restriction level of an application to a user. Otherembodiments are within the scope of the disclosed subject matter.

The disclosed module can be useful in prohibiting insecure datatransfers within an application instance. For example, if an applicationinstance is accessing a high security file retrieved from a computerreadable medium of a first security level, the module can update therestriction level of the application instance to the first securitylevel so that the application instance cannot write to another storagemedium having a lower security level than the high security level. Thisway, the module can prevent an application instance from copyinginformation from a high security file and storing the copied informationto a low security file. Furthermore, the module can prevent anapplication instance from saving a high security file as a low securityfile.

The disclosed module can also be useful in preventing insecure datatransfers across application instances. For example, the module can keeptrack of restriction levels associated with application instances, andnotify restriction levels of application instances to users. Bynotifying restriction levels, users can be prevented from inadvertentlycopying confidential information from a first application instance andstoring it using a second application instance.

FIG. 1 is a diagram of an exemplary networked communication system. Thenetworked communication arrangement 100 can include a communicationnetwork 102, a server 104, and at least one client 106 (e.g., client106-1, 106-2, . . . 106-N), a local network storage 108, a remotenetwork storage 110, and a correspondence table 112.

Each client 106 can send data to, and receive data from, the server 104over the communication network 102. Each client 106 can be directlycoupled to the server 104; alternatively, each client 106 can beconnected to server 104 via any other suitable device, communicationnetwork, or combination thereof. For example, each client 106 can becoupled to the server 104 via one or more routers, switches, accesspoints, and/or communication networks (as described below in connectionwith communication network 102). A client 106 can include, for example,a desktop computer, a mobile computer, a tablet computer, a cellulardevice, or any computing system that is capable of performingcomputation. The client 106 can also include a computer readable mediumfor storing data. The server 104 can be a single server, or a network ofservers, or a farm of servers in a data center. The server 104 caninclude a computer readable medium for storing data.

The communication network 102 can include a network or combination ofnetworks that can accommodate private data communication. For example,the communication network 102 can include a local area network (LAN), avirtual private network (VPN) coupled to the LAN, a private cellularnetwork, a private telephone network, a private computer network, aprivate packet switching network, a private line switching network, aprivate wide area network (WAN), a corporate network, or any number ofprivate networks that can be referred to as an Intranet. Such networksmay be implemented with any number of hardware and software components,transmission media and network protocols. FIG. 1 shows the network 102as a single network; however, the network 102 can include multipleinterconnected networks listed above.

The server 104 can be coupled to a network storage system. The networkstorage system can include two types of network storage devices: a localnetwork storage 108 and a remote network storage 110. The local networkstorage 108 and the remote network storage 110 can each include at leastone physical, non-transitory storage medium.

In some embodiments, the network storage system can be provided as anenterprise system in a corporate environment For example, thecommunication network 102 the proxy server 104, the clients 106, and thelocal network storage 108 can be located in a close proximity and can bea part of a single company. In contrast, the remote network storage 110can be operated by a third party vendor that provides a remote networkstorage service to the clients 106. In some cases, the proxy server 104,the clients 106, and the local network storage 108 can be located in thesame building and can be coupled to one another via a localcommunication network. The local communication network can include alocal area network (LAN,) a corporate network, and a virtual privatenetwork (VPN) associated with the corporate network.

In some embodiments, the local network storage 108 can operate underdifferent restrictions, security measures, authentication measures,and/or policies compared to the remote network storage 110. Theserestrictions, security measures, authentication measures, and/orpolicies can be set by a system administrator. In some cases, the localnetwork storage 108 can only be accessed by certain clients, based onthe location and/or the identification of the clients. For example,parts of the local network storage 108 can only be accessed by clientscoupled to the same local network as the server 104. In other cases, thelocal network storage 108 can use a predetermined encryption scheme forcommunication between the local network storage 108 and the clients. Inother cases, the local network storage 108 can only be accessed byclients that have recently been authenticated.

FIG. 1 shows the local network storage 108 as separate from thecommunication network 102. However, the local network storage 108 can bepart of communication network 102 or another communication network. FIG.1 shows the remote network storage 110 as separate from thecommunication network 102. However, the remote network storage 110 canbe part of the communication network 102 or another communicationnetwork. In some embodiments, the remote network storage 110 can becoupled to the Internet.

In some embodiments, the local network storage 108 or the remote networkstorage 110 can be configured as a distributed storage system havingmultiple storage devices coupled to the communication networks. Thedistributed storage system can include a Distributed Replicated BlockDevice (DRBD), a Distributed Network Block Device (DNBD), a DistributedFile System (DFS), and a Hadoop Distributed File System (HDFS).

In some embodiments, a computer readable medium, such as the computerreadable medium in the server 104, the client 106, and/or the networkstorages 108, 110 can be associated with a security level. In somecases, the entire computer readable medium or the entire network storagecan be associated with a single security level. In other embodiments, acomputer readable medium or a network storage can be divided intoportions, and each portion can be associated with a particular securitylevel. For example, a first portion of the computer readable medium canbe associated with a first security level, and a second portion of thecomputer readable medium can be associated with a second security levelthat is different from the first security level. In some cases, thecomputer readable medium or the network storage can be divided intoportions based on the underlying file directory structure. For example,a first folder of a computer readable medium can be associated with afirst security level, and a second folder of a computer readable mediumcan be associated with a second security level. A portion of the storagemedium or the network storage to which a particular security level canbe assigned can be referred to as a security zone.

In some embodiments, a computer system can maintain an associationbetween a security zone and its security level in a configuration file.The configuration file can maintain such associations using a datastructure, such as an array, an object, a table, a hash table, a map, orany other data structures that can maintain security zone—security levelpairs. The configuration file can include an encrypted text filecontaining JavaScript Object Notation (JSON) instructions to associate asecurity zone and a security level. The JSON instructions can include alist of structures where each structure includes a description of thesecurity zone, an identifier, a security level of the security zone andany other relevant information, including an amount of time out to limitthe maximum usage time of a security zone. In other embodiments, acomputer system can maintain the association between a security zone andits security level in a database.

In some cases, the configuration file can be maintained on a centralserver and can be “pushed” to a computer system. In other cases, it maybe desirable to store the configuration file in a storage medium thatcan be accessed rapidly. Rapid access to the configuration file may bedesirable to maintain the file system performance.

In some embodiments, a computer system can also associate a securitylevel to a data item. For example, the security level of a data item canbe set as the security level of the security zone in which the data itemis stored (e.g., the data item can automatically/manually inherit thesecurity level of the security zone). For example, if a data item isstored in a security zone of security level 3, the data item can beassociated with security level 3.

In some embodiments, a computer system can associate a running instanceof an application with a restriction level. A computer system candetermine a restriction level of an application instance based onsecurity levels of security zones that have been accessed by theapplication instance. In particular, the computer system can set arestriction level of an application instance as the highest securitylevel of all security zones from which the application instance hasretrieved data items (e.g., the application instance can inherit asecurity level that corresponds to the most-restrictive security zone ithas accessed). For example, if an application instance initiallyaccesses a security zone having security level 3, the computer systemassociates the application instance with restriction level 3. If thesame application instance, at a later time, accesses a security zonehaving security level 5, the computer system associates the applicationinstance with restriction level 5. However, if the same applicationinstance, at a later time, accesses a security zone with a securitylevel 1, the computer system does not update the restriction level ofthe application instance, as the restriction level of the applicationinstance is higher than the security level of the accessed securityzone. This restriction level update procedure can be a one-way process:the restriction level of an application instance preferably cannot belowered unless the application instance is terminated and restarted. Insuch embodiments, the only way to “lower” the restriction level is torestart the application instance.

In some embodiments, a computer system can associate a running instanceof an application with an access level. An access level of anapplication instance can be defined as the highest security level ofsecurity zones currently accessed by an application instance. Forexample, if an application instance is accessing a first security zonewith security level 1 and a second zone with security level 2, thecomputer system associates the application instance with access level 2.If the application instance releases the second security zone, theaccess level of the application would be downgraded to access level 1.

In some embodiments, a computer system can maintain an associationbetween an application instance and its restriction level in memory(e.g., the restriction level of an application can be persistent). Thecomputer system can also maintain an association between an applicationinstance and its access level in memory. The computer system canmaintain the associations using a data structure, such as an array, anobject, a table, a hash table, a map, or any other data structures thatcan represent application instance—restriction level pairs andapplication instance—access level pairs. In other embodiments, thecomputer system can maintain an association in a database.

In some embodiment, a security level of a security zone, a restrictionlevel of an application instance, and an access level of an applicationinstance can be represented as one of a plurality of candidate levels.The candidate levels can be a numerical value, an alphabetical value, astring of characters, or any combinations thereof.

A computer system, such as a server 104 and a client 106, can include amodule that can be configured to monitor application instances runningon the computer system or another computer system in order to enforce asecurity policy. For example, the module can be configured to police howthe application instances interact with security zones based onrestriction levels associated with the application instances andsecurity levels associated with the security zones.

At a high level, the module can be configured to receive a request froman application instance to authorize the application instance to write adata item to a security zone. Upon receiving the request, the module canauthorize or prevent the application instance from writing the data itemto the security zone based on the restriction level associated with theapplication instance and the security level associated with the securityzone. For example, the module can authorize the application instance towrite the data item to a security zone if the restriction level of theapplication instance is lower than the security level of the securityzone. In contrast, the module can prevent the application instance fromwriting the data item to the security zone if the restriction level ofthe application instance is higher than or equal to the security levelof the security zone. For instance, if an application instance isassociated with restriction level 3, the module can prevent theapplication instance from writing a data item to a security zone ofsecurity level 1.

FIG. 2 is a diagram showing an exemplary process of how a module canpolice write privileges of an application instance. FIG. 2 shows acomputer system having a module 202, an application space 204accommodating an application instance A 206 and an application instanceB 208, a security zone 1 210 associated with security level 1, asecurity zone 2 212 associated with security level 2, a restrictionlevel table (RLT) 214, and an access level table (ALT) 216. Theapplication instances 206, 208 can write data items to, and read dataitems from the security zones 210, 212, subject to the write privilegecontrol by the module 202.

The computer system can maintain a RLT 214, which can include a list ofentries, each entry indicating an application instance and a restrictionlevel associated with the application instance. In some cases, the RLTmay only maintain entries associated with currently running applicationinstances. The computer system can also maintain an ALT 216, which canincludes a list of entries, each entry indicating an applicationinstance and an access level associated with the application instance.In some aspects, the RLT 214 and the ALT 216 can refer to an applicationinstance using a process identifier (PID), used by the operating systemkernel to temporarily identify the application instance. For example,the RLT 214 and the ALT 216 use the PID associated with the applicationinstance A, PID_A, to refer to the application instance A; the RLT 214and the ALT 216 use the PID associated with the application instance B,PID_B, to refer to the application instance B.

In this illustration, the module 202 can authorize the applicationinstance A 206 to write to the security zone 1 210. The security levelof the security zone 1 210 is 1, and the restriction level of theapplication instance A 206 is also 1, as indicated by the restrictionlevel of PID_A in the RLT 214. Because the restriction level of theapplication instance A 206 is the same as the security level of thesecurity zone 1 210, the module 202 can authorize the applicationinstance A 206 to write to the security zone 1 210.

In contrast, the module 202 can prevent the application instance B 208from writing to the security zone 1 210. The security level of thesecurity zone 1 210 is 1, but the restriction level of the applicationinstance B 208 is 2, as indicated by the restriction level of PID_B inthe RLT 214. Because the restriction level of the application instance B208 is higher than the security level of the security zone 1 210, themodule 202 can prevent the application instance B 208 from writing tothe security zone 1 210. Note, however, that because the restrictionlevel of the application instance B 208 is the same as the securitylevel of the security zone 2 212, the module 202 can authorize theapplication instance B 208 to write to the security zone 2 212.

This module 202 can be useful in preventing a user from (1) retrieving asecure data item using an application instance, (2) copying informationfrom the secure data item, and (3) saving the information as an insecuredata item using the same application instance. For example, theapplication instance B 208 cannot copy information from document 3 andstore the copied information in document 2 because the module 202prevents the application instance B 208 from writing to the securityzone 1 210. This feature can ensure that secure information is notleaked to an unsecure computer readable medium within the sameapplication instance. Note also that the module 202 can control writeprivileges of applications without any prior knowledge of how theapplications operate. This is beneficial because the module 202 cancontrol write privileges of any type of applications running on any typeof computer systems.

FIGS. 3-5 are diagrams of exemplary processes for controlling writeprivileges of an application instance. In step 302, the module 202 candetect that an application instance is attempting to access a securityzone. For example, the module 202 can receive a request, from theapplication instance, to authorize access to a security zone. Once anattempted access is detected, the module 202 can determine the securitylevel associated with the security zone. In step 304, the module 202 candetermine whether the application instance is attempting to access thesecurity zone to read a data item from the security zone or whether theapplication instance is attempting to access the security zone to writea data item to the security zone. Based on that determination, themodule 202 can proceed with different procedures, as illustrated inFIGS. 4 and 5.

If the application instance is attempting to access the security zone toread a data item, then the module 202 can proceed to FIG. 4 to controlthe read operation of the application instance and, if necessary, toupdate the restriction level of the application instance. FIG. 4illustrates a process for controlling a read operation of an applicationinstance in accordance with some embodiments of the disclosed subjectmatter. In step 402, the module 202 can determine whether therestriction level table (RLT) 214 includes an entry indicating therestriction level of the application instance. In some cases, the module202 can search the RLT 214 using the process identifier (PID) of theapplication instance.

If the RLT 214 does not include an entry indicating the restrictionlevel of the application instance, in step 404, the module 202 canassociate the application instance with the restriction level, and addthe association to the RLT 214. In some embodiments, the module 202 canset the restriction level to be the same as the security level of thesecurity zone to be accessed by the application instance. For example,if the application instance is attempting to access a security zonehaving security level 2, the restriction level of the applicationinstance can be set to 2. Subsequent to adding the association of theapplication instance and the restriction level to the RLT 214, in step406, the module 202 can authorize the application instance to proceedwith the read operation. In some embodiments, the module 202 canauthorize the application instance to proceed with the read operation bysending an authorization message to the application instance.

In step 402, if the RLT 214 does include an entry indicating therestriction level of the application instance, the module 202 canproceed to step 408. In step 408, the module 202 can determine whetherthe restriction level of the application instance is higher than thesecurity level of the security zone to be accessed by the applicationinstance. If the restriction level of the application instance is higherthan the security level of the security zone, then in step 410, themodule 202 can associate the application instance with a new restrictionlevel and update the association in the RLT 214. In some cases, the newrestriction level associated with the application instance can be set asthe security level of the security zone. Subsequently, the module 202can proceed to step 406 and authorize the application instance toproceed with the read operation.

In step 408, if the restriction level of the application instance is nothigher than the security level of the security zone, then the module 202can proceed to step 406 and authorize the application instance toproceed with the read operation.

Referring back to FIG. 3, in step 304, if the application instance isattempting to access the security zone to write a data item or to updatea stored data item, then the module 202 can proceed to FIG. 5 to controlthe write operation of the application instance. FIG. 5 illustrates aprocess for controlling a write operation of an application instance inaccordance with some embodiments of the disclosed subject matter.

In step 502, the module 202 can determine whether the restriction leveltable (RLT) 214 includes an entry indicating the restriction level ofthe application instance. In some cases, the module 202 can search theRLT 214 using the process identifier (PID) of the application instance.

If the RLT 214 does not include an entry indicating the restrictionlevel of the application instance, in step 504, the module 202 canauthorize the application instance to proceed with the write operation.In some embodiments, the module 202 can authorize the applicationinstance to proceed with the write operation by sending an authorizationmessage to the application instance.

If the RLT 214 does include an entry indicating the restriction level ofthe application instance, the module 202 can proceed to step 506. Instep 506, the module 202 can determine whether the restriction level ofthe application instance is higher than the security level associatedwith the security zone to which the application instance attempts towrite. If the restriction level of the application instance is nothigher than the security level associated with the security zone, thenthe module can proceed to step 504 to authorize the application instanceto write to the security zone; If the restriction level of theapplication instance is higher than the security level associated withthe security zone, then the module can proceed to 508 to prevent theapplication instance from writing to the security zone.

While controlling write privileges of an application instance can beeffective in limiting data leakage to insecure security zones within theapplication instance, it may not be effective for data leakage acrossapplication instances. For example, referring to FIG. 2, a user can (1)copy information from document 3 of the application instance B 208,which is associated with the security zone 2 212 of security level 2,(2) paste the copied information to document 1 of the applicationinstance A 206, which is associated with the security zone 1 210 ofsecurity level 1, and (3) store the copied information as document 1 inthe security zone 1 210. This way, the user could work around the writeprivilege control to store confidential information of document 3 in thesecurity zone 1 210 with a lower security level.

In some embodiments, to limit data leakage across application instances,the module 202 can prohibit data communication between applicationinstances based on the restriction level of application instances. Insome embodiments, the module 202 can prevent a user from copyinginformation from an application instance of a high restriction level toanother application instance of a lower restriction level. To this end,the module 202 can detect a data transfer event, for example, anattempt, by a user, to copy information from a first data item of afirst application instance and to paste the copied information to asecond data item of a second application instance. In some aspects, themodule 202 can snoop on application-level messages to detect such a datatransfer event. Once the data transfer event is detected, the module 202can determine a first restriction level associated with the firstapplication instance and a second restriction level associated with thesecond application instance. If the first restriction level is higherthan the second restriction level, then the module 202 can prevent thedata transfer.

In some embodiments, to further limit data leakage across applicationinstances, the module 202 can notify users of the restriction levelsassociated with application instances. This way, it would be less likelythat a user inadvertently transfers data from a first applicationinstance having a high restriction level to a second applicationinstance having a lower restriction level. To this end, the module 202can cooperate with a notification application. For example, when anapplication instance is associated with restriction level 3, the module202 can cause the notification application to notify the user that therestriction level of the application instance is 3.

The disclosed notification application can notify restriction levelsand/or access levels, which are indicative of a security of the accesseddata. Notifying restriction levels and/or access levels is differentfrom notifying that a communication channel is secure since a securecommunication channel can be used to access data with a low securitylevel. Also, the disclosed notification application can notify therestriction level and/or access level of any type of application, suchas word processing applications, presentation applications, graphicdesign applications, and web browsers.

FIG. 6 is a diagram of an exemplary process for notifying a restrictionlevel of an application instance. In step 602, the notificationapplication determines which one of the application instances is aforeground application. The foreground application is an activeapplication that is displayed in the foreground of the user interface.In some instances, the notification application is configured to detectchanges in the foreground application. In particular, the notificationapplication can detect certain events that may change the foregroundapplication, and use those events as a triggering event for determiningthe foreground application. For example, a user interface can change theforeground application when a user selects one of the applications tobring it forward. Therefore, the notification application can detect aselection event initiated by the user, and, in response to the selectionevent, determine the foreground application.

If the foreground application has changed, the notification applicationcan determine the restriction level associated with the foregroundapplication. In some embodiments, the notification application candetermine the restriction level of the foreground application bycommunicating with a user interface control (UIC) module of the module202. For instance, the notification application can send a request tothe UIC module for the restriction level associated with the foregroundapplication. In response, the UIC module can send the restriction levelof the foreground application to the notification application. In otherembodiments, the notification application can maintain a copy of therestriction level table (RLT) 214 and use that copy of the RLT 214 todetermine the restriction level of the foreground application.

In step 604, the notification application can determine if therestriction level associated with the foreground application satisfiesnotification criteria. If the restriction level associated with theforeground application satisfies notification criteria, then in step606, the notification application can alert the user of theapplication's restriction level. If the restriction level associatedwith the foreground application does not satisfy the notificationcriteria, then in step 608, the notification application can remove anyexisting alerts.

In some embodiments, a restriction level associated with a foregroundapplication satisfies the notification criteria if the restriction levelis higher than a predetermined restriction level threshold. For example,the notification application can be configured to notify a user if therestriction level of the foreground application is greater than 3.

In other embodiments, a restriction level associated with a foregroundapplication satisfies the notification criteria if the restriction levelis an element in a notification group. A computer system can define anotification group at which the user should be notified. For example, anotification group can include restriction levels of “normal”,“relatively high”, and “high”. If the restriction level associated withthe foreground application is one of the elements in that notificationgroup, then the restriction level associated with the foregroundapplication would satisfy the notification criteria, and therefore thenotification application would notify the user.

In some embodiments, the notification application can notify the userusing a restriction level alert (RLA) icon. For example, a userinterface of an operating system, such as Windows or OS X, can include astatus bar. This status bar can be configured to maintain a RLA icon sothat whenever the restriction level of the foreground applicationsatisfies the notification criteria, the notification application canchange the appearance of the RLA icon.

In some cases, the notification application can change the color of theRLA icon; in other cases, the notification application can periodicallyblink the RLA icon; in other cases, the notification application canchange the shape of the RLA icon.

In some embodiments, the notification application can notify the userusing a sound cue. The sound cue can be different for differentrestriction level of the application instance. In some cases, thenotification application can provide the sound cue in conjunction withthe RLA icon.

In some embodiments, the notification application can alert the user bymodifying the appearance of a status bar in a user interface. FIGS.7A-7B are exemplary diagrams showing how a notification application canmodify an appearance of a status bar. FIG. 7A includes a user interface702, a status bar 704, an application instance 706 with a lowrestriction level, and an application instance 708 with a highrestriction level. In this illustration, a foreground applicationsatisfies the notification criteria if the restriction level of theforeground application is higher than a predetermined restriction levelthreshold. FIG. 7A illustrates a scenario in which the foregroundapplication is the application instance 706. Because the restrictionlevel of the application instance 706 is low and below the predeterminedrestriction level threshold, the application instance 706 does notsatisfy the notification criteria. Therefore, the notificationapplication leaves the status bar 704 in its default appearance.

FIG. 7B illustrates a scenario in which the application instance 708 isbrought to the foreground. When the application instance 708 is broughtto the foreground, the notification application can use the processillustrated in FIG. 6 to determine whether or not the notificationapplication should notify the user of the restriction level. In thiscase, because the restriction level of the application instance 706 ishigh and above the predetermined restriction level threshold, theapplication instance 706 does satisfy the notification criteria.Therefore, the notification application modifies the appearance of thestatus bar 704 to alert the user.

In some embodiments, the notification application modifies theappearance of status bar 704 by causing the user interface 702 to changethe color of the status bar 704, as illustrated in FIG. 7B. In otherembodiments, the notification application modifies the appearance ofstatus bar 704 by providing a colored, transparent box over the statusbar 704, thereby achieving a similar effect as causing the userinterface 702 to change the color of the status bar 704. In otherembodiments, the notification application modifies the appearance ofstatus bar 704 by providing a transparent, checkbox, hatched box, or ashaded box over the status bar 704.

In some embodiments, the module 202 can notify, to a user, an accesslevel associated with an application instance, instead of a restrictionlevel associated with an application instance. To this end, the module202 can compute an access level of an application using an access leveldetermination (ALT) module and cause the notification application tonotify a user of the access level associated with an applicationinstance using the user interface control (UIC) module.

To determine an access level of an application, the ALT module canmaintain or communicate with a security level table. The security leveltable can indicate, for each application instance, the number ofcurrently-accessed data items associated with each security level. FIG.8 is an illustration of an exemplary security level table. The securitylevel table (SLT) 802 includes two sub-tables 804A, 804B, one for eachapplication instance. Each sub-table includes a list of security levels806A, 806B supported by the computer system and, for each securitylevel, the number of currently-accessed data items 808A, 808B, retrievedfrom a security zone associated with the security level. For example,according to the sub-table 804A, the application instance A has fourdata items open, two data items retrieved from one or more securityzones having security level 2, one data item retrieved from a securityzone having security level 3, two data items retrieved from one or moresecurity zones having security level 5, and one data item retrieved froma security zone having security level 9.

The ALT module can generate or remove a sub-table 804 when anapplication instance is newly opened or closed, respectively. The module202 can update the sub-table 804 for an application instance when theapplication instance newly accesses a data item or when the applicationinstance releases an access to a currently-accessed data item.

The ALT module can determine the access level of an application instanceusing the security level table 802. In particular, the module 202 candetermine, from the sub-table of the application instance, the highestsecurity level for which the count 808 is non-zero. For the applicationinstance A (PID_A), the access level is 9; for the application instanceB (PID_B), the access level is 6.

In some embodiments, the module 202 can use a user interface control(UIC) module to cause the notification application to notify users ofaccess levels. For example, when an application instance is associatedwith access level 3, the UIC module can cause the notificationapplication to notify the user that the access level associated with theapplication is 3. The process for notifying the restriction level, asillustrated in FIGS. 6 and 7, can be easily adopted to notify the accesslevel.

FIG. 9 is a block diagram of an exemplary computing system. Thecomputing system 900 includes a processor 902, a memory 903, interfaces904-908, a module 202 including a restriction level determination module909, a security zone access control module 910, an access leveldetermination module 911, and a user interface control module 912, arestriction level table 214, an access level table 216, and a securitylevel table 802. The computing device 900 can communicate with othercomputing devices (not shown) via the interface 904; the computingdevice 900 can communicate with the local network storage 108 via theinterface 905; the computing device 900 can communicate with the remotenetwork storage 110 via the interface 906; the computing device 900 cancommunicate with the Intranet 913 via the interface 907; and thecomputing device 900 can communicate with the Internet 914 via theinterface 908. The interfaces 904-908 are shown as separate interfacesbut may be the same physical interface.

In some embodiments, the processor 902 is configured to run anapplication instance in a user space of an operating system. Theprocessor 902 is also configured to run a notification application inthe user space of the operating system. The processor 902 can includeone or more cores and can accommodate one or more threads to run theapplication instance and the notification application.

The restriction level determination (RLD) module 909 can be configuredto determine a restriction level associated with an applicationinstance. For example, when an application instance requests a readaccess to a security zone, the RLD module 909 can determine whether theapplication instance is associated with a restriction level. If theapplication instance is not associated with a restriction level, thenthe RLD module 909 can set the restriction level of the applicationinstance as the security level of the security zone. If the applicationinstance is associated with a restriction level, then the RLD module 909can determine if the security level of the security zone is higher thanthe restriction level of the application instance. If so, then the RLDmodule 909 can update the restriction level of the application instanceas the security level of the security zone. If not, then the RLD module909 does not update the restriction level of the application instance.

The security zone access control (SAC) module 910 can be configured tocontrol write privileges of an application instance. For example, whenan application instance can request a write access to a security zone,the SAC module 910 can determine whether the application instance isassociated with a restriction level. If the application instance is notassociated with a restriction level, then the SAC module 910 canauthorize the application instance to write to the security zone. If theapplication instance is associated with a restriction level, then theSAC module 910 can determine if the restriction level of the applicationinstance is higher than the security level of the security zone. If so,then the SAC module 910 can prevent the application instance fromwriting to the security zone; if not, then the SAC module 910 can allowthe application instance to write to the security zone.

The access level determination (ALD) module 911 can be configured todetermine the access level of application instances. In some cases, theALD module 911 can use a security level table 802 to determine theaccess level, and maintain the access level of application instances inan access level table 216.

The user interface control (UIC) module 912 can be configured tocooperate with a notification application to notify users of an alertlevel associated with an application instance. In particular, the UICmodule 912 can provide the alert level associated with activeapplication instances to the notification application. The alert levelcan include at least one of a restriction level or an access level.

In some embodiments, the module 202 can be implemented in a kernel spaceof an operating system. In particular, the module 202 can be implementedas a kernel based restriction implemented in the kernel space of anoperating system. The kernel based restriction can operate as anintermediary between a user space (in which an application instanceoperates) and hardware components of a computing system. The kernelbased restriction and the user space can use a kernel interface forcommunication. The kernel interface can include Portable OperatingSystem Interface (POSIX),

The kernel based restriction can authorize an application instance toaccess a hardware component, such as a storage medium. For example, whenan application instance, running in a user space of the operatingsystem, attempts to write a data item in a storage medium, theapplication instance can send an authorization request to the kernelbased restriction, requesting a write access to a storage medium. Theauthorization request can be a system call defined in an operatingsystem-specific header file. In response, the kernel based restrictioncan determine whether or not the application instance is authorized towrite the data item in the storage medium. If the application instanceis authorized to write the data item, then the kernel based restrictioncan send an acknowledgment message to the application instance,authorizing the application instance; if the application instance is notauthorized to write the data item, then the kernel based restriction cansend a rejection message to the application instance, indicating thatthe application instance cannot access the storage medium.

In some embodiments, the kernel based restriction can be implementedusing a kernel, or a loadable kernel module for a kernel. The loadablekernel module is an object file that extends capabilities of the kernelof an operating system. The loadable kernel module is often used tosupport additional system calls, new hardware, and/or new file systems.For example, the kernel based restriction can be implemented as aloadable kernel module that is registered as a callback, also known as alistener, that makes an authorization decision for accessing storagemedia.

In other embodiments, the kernel based restriction can be implemented asa microkernel, a loadable kernel module for a microkernel, a KernelAuthorization (Kauth) system, or a loadable kernel module for a Kauthsystem. In some operating systems, the loadable kernel module is alsoreferred to as a kernel extension (Kext).

In other embodiments, the module 202 can include an access control list(ACL.) The ACL can maintain which application instance can accesscertain security zones. In some embodiments, the module 202 can beimplemented as an application running in an application space of acomputer system.

In some embodiments, the module 202 can be implemented on a stand-alonecomputing system, such as a client 106, to provide access control to thecomputing system's local storage medium. In other embodiments, themodule 202 can be implemented on a server 104 for providing an accesscontrol service to clients 106. For example, the module 202 can controlaccess of server's local storage or the network storages 108, 110 byclients 106. In another example, the module 202, implemented on a server104, can control client's access of its own local storage medium.

The notification application (NA) module 913 can be configured to notifyan alert level associated with a foreground application instance tousers. The NA module 913 can determine when a user interface, such as adesktop screen, brings an application instance to a foreground. The userinterface can bring an application instance to the foreground inresponse to a predetermined event. For instance, the user interface canchange the foreground application when a user selects an applicationinstance from a background.

Once the NA module 913 determines that an application instance is in aforeground, the NA module 913 can determine an alert level associatedwith the foreground application instance. To this end, the NA module 913can communicate with the UIC module 912. For example, the NA module 913can request the UIC module 912 to provide an alert level associated withthe foreground application instance. In response to the request, the UICmodule 912 can provide the requested alert level to the NA module 913.The alert level can include a restriction level and/or an access level.

Upon determining the alert level associated with the foregroundapplication instance, the NA module 913 can notify the alert level tothe user using visual cues. In some cases, the NA module 913 can notifythe alert level using an alert level notification icon. The alert levelnotification icon can be located in a status bar of the user interface.In other cases, the NA module 913 can notify the alert level by changingan appearance of a status bar in the user interface. For example, the NAmodule 913 can cause a perceived change of color in the status bar.

In some embodiments, the module 202 and the NA module 913 can beimplemented in software stored in the memory 903. The memory 903 can bea non-transitory computer readable medium, flash memory, a magnetic diskdrive, an optical drive, a programmable read-only memory (PROM), aread-only memory (ROM), or any other memory or combination of memories.The software can run on a processor 902 capable of executing computerinstructions or computer code. The processor 902 might also beimplemented in hardware using an application specific integrated circuit(ASIC), programmable logic array (PLA), field programmable gate array(FPGA), or any other integrated circuit.

FIG. 9 shows a computing system 900 having a module 202 that perform theabove-described operations in accordance with some embodiments of thedisclosed subject matter. The computing system 900 may includeadditional modules, less modules, or any other suitable combination ofmodules that perform any suitable operation or combination ofoperations.

The interfaces 904-908 provide an input and/or output mechanism forcommunication. In some cases, the interfaces 904-908 can be used tocommunicate within the computing system. For example, the processor 902can use one of the interfaces 904-908 to communicate with memory 903. Inother cases, the interface 904-908 can be used to communicate over anetwork. The interfaces 904-908 enable communication with othercomputing systems, such as clients 106 and servers 104, as well as othernetwork nodes in the communication network 102. The interfaces 904-908can be implemented in hardware to send and receive signals in a varietyof mediums, such as optical, copper, and wireless, and in a number ofdifferent protocols some of which may be non-transient.

The computing system 900 can operate using an operating system (OS)software. In some embodiments, the OS software is based on a Linuxsoftware kernel and runs specific applications in the computing system900 such as monitoring tasks and providing protocol stacks. The OSsoftware allows resources to be allocated separately for control anddata paths. For example, certain packet accelerator cards and packetservices cards are dedicated to performing routing or security controlfunctions, while other packet accelerator cards/packet services cardsare dedicated to processing user session traffic. As networkrequirements change, hardware resources can be dynamically deployed tomeet the requirements in some embodiments.

The system's software can be divided into a series of tasks that performspecific functions. These tasks communicate with each other as needed toshare control and data information throughout the computing system 900.A task can be a software process that performs a specific functionrelated to system control or session processing. Three types of tasksoperate within the computing system 900 in some embodiments: criticaltasks, controller tasks, and manager tasks. The critical tasks controlfunctions that relate to the computing system's ability to process callssuch as initialization, error detection, and recovery tasks. Thecontroller tasks can mask the distributed nature of the software fromthe user and perform tasks such as monitoring the state of subordinatemanager(s), providing for intra-manager communication within the samesubsystem, and enabling inter-subsystem communication by communicatingwith controller(s) belonging to other subsystems. The manager tasks cancontrol system resources and maintain logical mappings between systemresources.

Individual tasks that run on processors in the application cards can bedivided into subsystems. A subsystem is a software element that eitherperforms a specific task or is a culmination of multiple other tasks. Asingle subsystem includes critical tasks, controller tasks, and managertasks. Some of the subsystems that run on the computing system 900include a system initiation task subsystem, a high availability tasksubsystem, a shared configuration task subsystem, and a resourcemanagement subsystem.

The system initiation task subsystem can be responsible for starting aset of initial tasks at system startup and providing individual tasks asneeded. The high availability task subsystem can work in conjunctionwith the recovery control task subsystem to maintain the operationalstate of the computing system 900 by monitoring the various software andhardware components of the computing system 900. Recovery control tasksubsystem can be responsible for executing a recovery action forfailures that occur in the computing system 900 and receives recoveryactions from the high availability task subsystem. Processing tasks canbe distributed into multiple instances running in parallel so if anunrecoverable software fault occurs, the entire processing capabilitiesfor that task are not lost. User session processes can be sub-groupedinto collections of sessions so that if a problem is encountered in onesub-group users in another sub-group will not be affected by thatproblem.

Shared configuration task subsystem can provide the computing system 900with an ability to set, retrieve, and receive notification ofconfiguration parameter changes and is responsible for storingconfiguration data for the applications running within the computingsystem 900. A resource management subsystem can be responsible forassigning resources (e.g., processor and memory capabilities) to tasksand for monitoring the task's use of the resources.

In some embodiments, the computing system 900 can reside in a datacenter and form a node in a cloud computing infrastructure. Thecomputing system 900 can also provide services on demand. A modulehosting a client is capable of migrating from one computing system toanother system seamlessly, without causing program faults or systembreakdown. The computing system 900 on the cloud can be managed using amanagement system.

The client 106 can include user equipment. The user equipmentcommunicates with one or more radio access networks and with wiredcommunication networks. The user equipment can be a cellular phonehaving phonetic communication capabilities. The user equipment can alsobe a smart phone providing services such as word processing, webbrowsing, gaming, e-book capabilities, an operating system, and a fullkeyboard. The user equipment can also be a tablet computer providingnetwork access and most of the services provided by a smart phone. Theuser equipment operates using an operating system such as Symbian OS,iPhone OS, RIM's Blackberry, Windows Mobile, Linux, HP WebOS, andAndroid. The screen might be a touch screen that is used to input datato the mobile device, in which case the screen can be used instead ofthe full keyboard. The user equipment can also keep global positioningcoordinates, profile information, or other location information.

The computing system 900 can be a client 106. The client 106 alsoincludes any platforms capable of computations and communication.Non-limiting examples can include televisions (TVs), video projectors,set-top boxes or set-top units, digital video recorders (DVR),computers, netbooks, laptops, and any other audio/visual equipment withcomputation capabilities. The client 106 is configured with one or moreprocessors that process instructions and run software that may be storedin memory. The processor also communicates with the memory andinterfaces to communicate with other devices. The processor can be anyapplicable processor such as a system-on-a-chip that combines a CPU, anapplication processor, and flash memory. The client 106 can also providea variety of user interfaces such as a keyboard, a touch screen, atrackball, a touch pad, and/or a mouse. The client 106 may also includespeakers and a display device in some embodiments.

Throughout the disclosure, the term “application instance” is generallyused to refer to an instance of an application or software to which aprocess identifier is assigned by an operating system. In some cases, acomputer system can have multiple instances of the same application. Forexample, OS X can run multiple instances of Safari web browsers. In someembodiments, the application instance can include one or more processesthat collaborate to run an application instance. Other embodiments of an“application instance” are within the scope of the disclosed subjectmatter.

Throughout the disclosure, the term “data item” is generally used torefer to a sequence of bits carrying information. The data item caninclude a file, a document, a record, contents of a file, a page inmemory, a digital message, or any other entity that can be representedby a sequence of bits. Other embodiments of an “data item” are withinthe scope of the disclosed subject matter.

Although the disclosed subject matter has been described and illustratedin the foregoing exemplary embodiments, it is understood that thepresent disclosure has been made only by way of example, and thatnumerous changes in the details of implementation of the disclosedsubject matter may be made without departing from the spirit and scopeof the disclosed subject matter, which is limited only by the claimswhich follow.

What is claimed is:
 1. An apparatus comprising: a non-transitory memorystoring computer readable instructions; a processor in communicationwith the memory and with a non-transitory computer readable mediumhaving a first security zone, wherein the computer readable instructionsare configured to cause the processor to: receive a request, from anapplication instance running in a user space of an operating system, toaccess the first security zone, wherein the first security zone isassociated with a first security level; determine whether a restrictionlevel associated with the application instance is higher than the firstsecurity level, wherein the restriction level associated with theapplication instance is a function of previous security zones that havebeen accessed by the application instance; when the restriction levelassociated with the application instance is higher than the firstsecurity level, prevent the application instance from accessing thefirst security zone; and when the restriction level associated with theapplication instance is not higher than the first security level,authorize the application instance to access the first security zone. 2.The apparatus of claim 1, wherein the non-transitory memory furthercomprises instructions that cause the processor to: determine whetherthe application instance is associated with any restriction level; andwhen the application instance is not associated with any restrictionlevel, authorize the application instance to access the first securityzone.
 3. The apparatus of claim 1, wherein the non-transitory memoryfurther comprises instructions that cause the processor to: receive arequest, from the application instance, to authorize a read operation toa second security zone of the computer readable medium, wherein thesecond security zone is associated with a second security level;determine whether the restriction level associated with the applicationinstance is higher than the second security level; and when therestriction level associated with the application instance is higherthan the second security level, modify the restriction level of theapplication instance as the second security level.
 4. The apparatus ofclaim 3, wherein the non-transitory memory further comprisesinstructions that cause the processor to: determine whether theapplication instance is associated with any restriction level; and whenthe application instance is not associated with any restriction level,associate the application instance with a restriction level, wherein therestriction level is set as the second security level.
 5. The apparatusof claim 1, wherein the restriction level associated with theapplication instance is a highest security level of all previoussecurity zones that have been accessed by the application instance. 6.The apparatus of claim 1, wherein the instructions are configured to beexecuted in a kernel space of the operating system.
 7. The apparatus ofclaim 6, wherein the instructions comprise a loadable kernel moduleconfigured to be executed in the kernel space of the operating system.8. The apparatus of claim 1, wherein the association between the firstsecurity zone and the first security level is maintained in aconfiguration file stored in the non-transitory memory.
 9. The apparatusof claim 1, wherein the request to access the first security zoneincludes a request to authorize a write operation to the first securityzone.
 10. A non-transitory computer readable medium having executableinstructions operable to cause an apparatus to: identify an attempt, byan application instance running in a user space of an operating system,to access a first security zone of non-transitory memory, wherein thefirst security zone is associated with a first security level; determinewhether a restriction level associated with the application instance ishigher than the first security level, wherein the restriction levelassociated with the application instance is a function of previoussecurity zones that have been accessed by the application instance; whenthe restriction level associated with the application instance is higherthan the first security level, prevent the application instance fromwriting to the first security zone; and when the restriction levelassociated with the application instance is not higher than the firstsecurity level, authorize the application instance to access the firstsecurity zone.
 11. The computer readable medium of claim 10, furthercomprising executable instructions operable to cause the apparatus to:determine whether the application instance is associated with anyrestriction level; and when the application instance is not associatedwith any restriction level, authorize the application instance to accessthe first security zone.
 12. The computer readable medium of claim 10,further comprising executable instructions operable to cause theapparatus to: identify an attempt by the application instance to performa read operation to a second security zone of the computer readablemedium, wherein the second security zone is associated with a secondsecurity level; determine whether the restriction level associated withthe application instance is higher than the second security level; andwhen the restriction level associated with the application instance ishigher than the second security level, modify the restriction level ofthe application instance as the second security level.
 13. The computerreadable medium of claim 12, further comprising executable instructionsoperable to cause the apparatus to: determine whether the applicationinstance is associated with any restriction level; and when theapplication instance is not associated with any restriction level,associate the application instance with a restriction level, wherein therestriction level is set as the second security level.
 14. A methodcomprising: identifying, by a module in a computer system, an attempt toaccess, by an application instance running in a user space of anoperating system, a first security zone of a computer readable medium,wherein the first security zone is associated with a first securitylevel; determining, by the module, whether a restriction levelassociated with the application instance is higher than the firstsecurity level, wherein the restriction level is a function of previoussecurity zones that have been accessed by the application instance; whenthe restriction level associated with the application instance is higherthan the first security level, preventing the application instance fromwriting to the first security zone; and when the restriction levelassociated with the application instance is not higher than the firstsecurity level, authorizing the application instance to access the firstsecurity zone.
 15. The method of claim 14, further comprising: receivinga request, from the application instance, to authorize a read operationto a second security zone of the computer readable medium, wherein thesecond security zone is associated with a second security level;determining whether the restriction level associated with theapplication instance is higher than the second security level; and whenthe restriction level associated with the application instance is higherthan the second security level, modifying the restriction level of theapplication instance as the second security level.
 16. The method ofclaim 14, wherein the association between the first security zone andthe first security level is maintained in a configuration file stored inmemory.
 17. The method of claim 14, wherein the module in the computersystem is running in a kernel space of the operating system.
 18. Themethod of claim 17, wherein the module comprises a loadable kernelmodule running in the kernel space of the operating system.
 19. Themethod of claim 17, wherein identifying the attempt to access the firstsecurity zone comprises receiving, from the application instance, asystem call to authorize a write operation to the first security zone.20. The method of claim 17, wherein authorizing the application instanceto access the first security zone comprises sending, via an interfacebetween the kernel space and the user space, an acknowledgment messageto the application instance, indicating that the application instance isauthorized to perform a write operation to the first security zone.